The present disclosure and claims, in general, relate to a liquid coating, coating material or suspension for application to at least one cellulosic fiberboard, fiberboard material, roofing board, roofing board material or other suitable construction material meeting, for example, and preferably ASTM standard C208 for roof system applications. Fiberboard meeting ASTM C208 generally has a coating applied to at least one side of board. The coating is particularly important to certain roofing systems, such as systems that have a membrane (e.g., thermoplastic polyolefin (T.P.O.), polyvinyl chloride vinyl (P.V.C.), ethylene propylene diene monomer (E.P.D.M.) single-ply and/or multi-ply and any other common and uncommon roofing system known to one of skill in the relevant art) attached with an adhesive, such as a liquid adhesive, foam adhesive or peel and stick applications. Solvent and water based adhesives are suitable examples of adhesives that may be used in conjunction with the coatings of the present technology and have demonstrated a unique ability to bond successfully without the poor membrane adhesion commonly associated with asphaltic coated fiberboard.
To attach a membrane, for example a single-ply or multi-ply membrane(s), an adhesive is applied to the surface of the board before applying a membrane. Without a coating, the adhesive can soak or strike into the fiberboard too deeply which can, in turn, result in a weak bond or the need to increase the application rate and/or the amount of adhesive applied. The liquid fiberboard coating is particularly important when certain adhesives, such as water based adhesives, are used because these adhesives exhibit an increased propensity to soak or strike into the fiberboard.
Asphalt based coatings for fiberboard became widespread prior to the use of membranes, such as single-ply or multi-ply membrane(s), in conjunction with the roofing fiberboards. This may have led to the general idea that roofing board is expected to be black in color and to the idea that the black color of a roofing board was accepted to indicate a quality product. However, asphalt based coatings are not generally recommended to be used for fiberboards that include a membrane, such as T.P.O., P.V.C. or EPDM single-ply or multi-ply membrane system(s). This is due to the fact that asphalt based coatings result in poor membrane adhesion and/or degradation of membrane. Therefore, there was a need in the art for non-asphalt based liquid coatings for roofing fiberboards that are used in conjunction with membranes.
Generally, non-asphalt based liquid coatings for roofing system fiberboards that include attached membranes have utilized carbon black as a colorant. This is likely a result of the previous general acceptance of idea that the black color indicated a quality product. However, the use of carbon black in current roofing fiberboard coatings is detrimental because the carbon black absorbs solar energy and, thereby, could contribute to curling of the fiberboard. Curling of the fiberboard is particularly problematic with roofing fiberboards because it can cause irregularities that interfere with the application of the membrane to the fiberboard. Therefore, the instant Applicants recognized that there is a current need in the art to replace carbon black as the pigment in non-asphalt based roofing fiberboard coatings in order to produce a higher quality non-asphalt coating that is compatible for use with adhesive applied membranes and that inhibits moisture loss and curling.
The instant Applicants have also discovered that replacing carbon black with a solar reflecting pigment or additive will reduce curling which will improve application of membrane. The first objective of the current technology, in certain embodiments, is to provide a coating with a color other than black. This non-black color feature is advantageous because it will facilitate recognition of the fiberboards coated with certain embodiments of the present technology and distinguish fiberboards coated with the present coatings from asphalt coated fiberboards. This will enable membrane installers to be confident that they are affixing membranes to the appropriate fiberboards that contain a non-asphalt based coating. Red iron oxide, yellow iron oxide and titanium dioxide are very effective in reducing solar heat gain. Coatings made with these solar reflectors have a color range of pink to red and yellow to orange. These coating colors allow for easy recognition that the coatings are asphalt free. The inclusion of thermal insulating particles in coatings has some impact on the color of the coating. In general these thermal insulating particles reduce the intensity of the coating color without interfering with the solar reflectance. Red and Yellow iron oxide are effective as solar reflectors. While titanium dioxide is very effective in reflecting solar energy, the lower cost coating made with yellow or red iron oxide or combinations of the two oxides are effective. Titanium dioxide may be added as a component of this solar reflective coating, but its use may be limited due to the cost of titanium dioxide.
The second separate objective of the present technology is to decrease the curling rate of a fiberboard that is exposed to direct solar light. This curling results when heat causes moisture to evaporate or move away from an exposed surface. Sealing the fiberboard surface with a clear sealer known to prevent moisture transfer does not stop curling. However, sealing the fiberboard with a particular embodiment of the present technology was found to provide advantages with respect to moisture transfer and/or loss and decreased curling. Metal flakes or insulating particles coated with reflective metal is also effective at reducing solar heat gain and curl.
One aspect of the present technology is a fiberboard meeting ASTM standard C208 or similar fiberboard comprising: at least one fiberboard; a sufficient amount of at least one reflective and/or shielding coating capable of reducing moisture loss and curl of the fiberboard or reduced energy transfer though board when the fiberboard is exposed to solar energy; a reflective and/or shielding agent selected from the group consisting of red iron oxide, yellow iron oxide, magnetic iron oxide, titanium dioxide, and combinations thereof; wherein the coated fiberboard contains at least 0.5 pounds of reflective and/or shielding agent per thousand square feet of board and enough of a binder or adhesive to attach reflective and/or shielding agent to the surface of fiberboard. For cellulosic roofing and insulation board weighing about 24 pounds per cubic foot, this application rate for a one inch board would be about 0.5 pounds or greater of reflective and/or shielding agent per 83.3 cubic foot or 0.5 pounds per 2000 pounds of fiberboard. As the density of the fiberboard decreases, more reflective and/or shielding agent is used per pound of cellulosic fiberboard. For example, when a one inch fiberboard weighs 12 pounds per cubic foot, the agent would be applied at a rate of 0.5 pounds per 1000 pounds of fiberboard.
It should be appreciated that the coatings of the present technology are compatible with, and can be used in conjunction with, any variety of cellulosic fiberboard known to one of skill in the relevant art. Examples of some relevant fiberboards and processes of making those fiberboards can be found, for example, in U.S. Pat. Nos. 7,815,772; 8,057,638; 8,038,845; 8,241,463; 8,382,951; 8,382,952 and 8,382,953, the contents of all of which are hereby incorporated by reference in their entireties. A third separate objective with this coating technology is to reduce the quantity of adhesive needed to attach the membrane to the fiberboard.